Color Doppler imaging is used to detect motion in ultrasound images. It is commonly used to detect or qualitatively assess blood flow but has also has applications in cardiology to measure motion of the heart wall (so called “tissue Doppler imaging”). Color Doppler images provide flow information over a two dimensional region. Color Doppler imaging lacks the quantitative accuracy or sensitivity of pulse Doppler or continuous wave Doppler. Sensitivity and spatial resolution are competitive characteristics of color Doppler imaging.